著者

村田 亮 黒田 重史 石毛 徳之 荻野 修平 三笠 元彦

出版者

日本肩関節学会

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.36, no.3, pp.1015-1018, 2012 (Released:2012-10-25)

参考文献数

11

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Background: The scapula rotates upwardly during shoulder elevation. If the rotation center wasn't fixed on the scapula but on the humeral head, the movement of the glenoid would be regarded as the rotation along the humeral head. We have analyzed throwing shoulder injury cases using this concept of “functional glenoid”.Methods: Patients with throwing shoulder injury (TSI group; n=22) and normal control (n=8) were included in the study. Two radiographs were taken of each subject (anteroposterior in internal rotation; IR1, zero position). Two straight lines were drawn from the superior and inferior tubercle to the center of the humeral head in IR1 image, and the angle of the lines was measured (α angle). The TSI group was divided to two groups according to slipping of the humeral head in zero position images. The difference of the glenoid inclination angles between IR1 and zero position (β angle) were then measured, and the glenoid extension ratio (α+β/α) was calculated. Each set of data was statistically evaluated.Results: In the TSI group, β angle and the glenoid extension ratio did not show significant difference compared to the control group, but the slipping-negative cases showed significantly larger β angle than slipping-positive cases and the control group.Discussion: These results may be derived from multifactorial pathology of throwing shoulder injury. Significantly large β angle in slipping-negative TSI cases may indicate an adaptive pattern of movement of the scapula. The glenoid extension ratio could not reflect the scapular kinematic change of throwing shoulder injury.